function select(sel){
    const ele = document.querySelector(sel);
    ele.css = function(ops){
        for(let i in ops){
            this.style[i] = ops[i];
        }
        return this;
    }
    ele.html = function(val){
        this.innerHTML = val;
        return this;
    }
    ele.attr = function(ops){
        for(let i in ops){
            this.setAttribute(i, ops[i]);
        }
    }
    // .......
    return ele;
}

select.ajax = function(){
    console.log("这是jq的ajax")
}